Send Reaction

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, covering the basic safety profile. The description adds no behavioral context beyond the obvious action, such as whether the reaction can be removed or how it interacts with existing reactions. It is adequate but unhelpful beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single clear sentence with no redundant words. It wastes no tokens and is easily digestible.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool with three fully documented parameters and annotations covering the operation type, the description is sufficiently complete. It doesn't explain return values, but no output schema exists, and the action is straightforward. Lacks any mention of edge cases (e.g., invalid message ID), but these are not essential for basic use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with each parameter clearly documented (e.g., emoji description mentions empty string to remove). The description itself adds no parameter-level meaning, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (react) and the resource (specific WhatsApp message) with a distinctive tool purpose. It differentiates from siblings like send_text or send_media by specifying 'react' with an emoji, which is a unique behavior.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool vs alternatives. The description merely states the action without mentioning context, prerequisites, or exclusions (e.g., 'Use this instead of send_text to add a reaction'). This is a clear gap.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.